Question

if a+b+c=9if a + b + c = 9 and a b + BC + CA = 40 then find a raise to power to +b raised to power 2+ 3 raise to power 2

Answer 1

the formula of (a+b+c)to the power 2 is (a to the power 2 +b to the power 2+c to the power 2)*(ab +bc +ca)
given a+b+c=9 and ab +bc +ca =40 
so
9 to the power 2=(a^2+b^2+c^2)*40
81 -40 =a^2+b^2+c^2
41